Practitioners in the fields of ophthalmology and optometry often will use hand-held devices and the like to make an examination of the eye of the patient, such as disclosed in U.S. Pat. No. 5,046,836. U.S. Pat. No. 4,196,980 discloses in FIGS. 2 and 3 examination patterns 3' projected onto the retina of the eye, as another example of a hand-held device.
It is also known in the prior art that an ophthalmologist or optometrist may use mechanical devices for holding an examining lens relative to a patient's eye, such as one attached to a special headband worn by the examiner, so as to free his or her hands, perhaps for the purpose of holding the eyelid of the patient in position, or of moving other devices between the mechanical device being held and the eye of the patient, such as shown in FIG. 3 of U.S. Pat. No. 4,900,143.
It is further known to attach holders to the head rest of a slit lamp biomicroscope relative to the location of the eyes of the patient. U.S. Pat. No. 4,934,809, for instance, discloses a lens positioning device, which is attached to one of the chin rest vertical bars of a slit lamp biomicroscope and includes a plurality of movable arms for positioning a lens relative to the eye of the patient.